In a conventional image forming apparatus, a toner image formed on a photoreceptor drum is transferred onto a sheet. In such image forming apparatus, for example, the surface of the photoreceptor needs to be cleaned in order to form a high quality image. For this purpose, there is known a technique in which, when matter stuck to the photoreceptor are collected by a photoreceptor cleaner, a belt cleaner is able to collect the stuck matters via the photoreceptor cleaner and a belt at a predetermined timing.
The above described technique needs time to performing the collecting processing separately from the image formation processing time (printing time), and thus resulting in the throughput of image formation to be slowed, which causes image formation to be inefficient. Thus, there is a need in the art for an image forming apparatus capable of effectively collecting matter stuck to the photoreceptor, and highly efficiently realizing both the collecting processing and the image formation processing without disadvantageously slowing the throughput of image formation.